The present invention is related to a wind energy plant with a rotor hub, which is equipped with at least one pitch bearing.
The pitch bearing is a rolling bearing with an inner and an outer ring, one of the rings being connected to the rotor hub and the other ring being connected to the rotor blade. Thus, via a pitch drive, the rotor blade can be rotated around its longitudinal axis and its angle of attack can be adjusted towards the wind.
Known rotor hub constructions consist of a cast body with a flange for joining the pitch bearing. Erich Hau describes in “Windkraftanlagen, Grundlagen, Technik, Einsatz, Wirtschaftlichkeit, 3th edition, Springer Verlag Berlin” in chapter 7.5, the entire contents of which is incorporated herein by reference, that the quality and the weight of the rotor blades is essentially determined by the construction of the blade joining to the rotor hub, besides to the proper execution of the rotor blade. The constructive realisation of the blade joining on the rotor hub should belong to the most demanding goals of rotor blade development. Among the different realisations of the rotor blade joining there is the double-sided steel flange in which the blade root is clamped between an inner and an outer flange and the two flanges are screwed together with each other. The junction to the rotor hub takes then place via a lapped flange located at the outside. A further concept which has proven to be particularly weight-saving is laminated joining bolts, which are directly laminated into the rotor blade root structure. A further concept is to provide aviation-type laminated flanges or fastening sleeves in the rotor blade root, in order to join it with the rotor hub.
From DE 10 2004 023 773 B3, the entire contents of which is incorporated herein by reference, it is known to realise the pitch bearing with an inner ring, which is fixedly connected to the rotor hub, and with an outer ring which is fixedly connected to the rotor blade. The outer ring has an outer toothing which is in meshing engagement with a drive sprocket for adjusting the rotor blade.
From DE 10 2004 017 323 A1, the entire contents of which is incorporated herein by reference, a blade joining for a rotor blade is known, in which an arresting device is provided, which keeps the rotor blade free from backlash in a predetermined angle position.
From WO 2004/090326 A1, the entire contents of which is incorporated herein by reference, a rotor hub is known, which has a three-arm stiffening, formed in one piece in the region of the rotor blade joining.
The present invention is based on the objective to provide a blade joining for a rotor blade on a rotor hub, which avoids a too great load of the pitch bearing with simple means.